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  • What is a modern C++ approach to structures containing symbolic constants?

    - by Ken
    enum bool { FALSE = 0, TRUE = 1 }; I'm wondering how to translate this in a modern C++ approach and if there is a well suited container for that; i know that the enum are not really that appreciated, but i can't think about a real alternative in the C++ world. What if would like to associate the execution of a particular method with a state? Ok, this is the part where i will be more verbose. I would like to stress the fact that i'm asking about structures symbolic constants and not about TRUE and FALSE, i'm not that "needy". Suppose that i have a structure that can represent several states with their own constants enum semaphore { GREEN = 0, ORANGE = 1, RED = 2 }; this is C code, now my question is about how to do the same in C++ if there is a better way. My question continue when i ask about the possibility to do something like an automatic triggering when a change of state will occur, for example: int main{ ... semaphore = 1; ... } and without any extra statements this has to trigger a method() just because the semaphore is now orange. I hope that is more clear now.

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  • How can you tell which columns are unused in ALL_TAB_COLS?

    - by thecoop
    When you query the ALL_TAB_COLS view on Oracle 9i, it lists columns marked as UNUSED as well as the 'active' table columns. There doesn't seem to be a field that explicitly says whether a column is UNUSED, or any view I can join to that lists the unused columns in a table. How can I easily find out which are the unused columns, so I can filter them out of ALL_TAB_COLS?

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  • Generate sample XML from composite hierarchical structure

    - by Jevgenij Nekrasov
    Let's say I have composite hierarchical structure. Each object in the structure has child collection of the same objects. Each object has XPath property, which stores the exact xpath to the element inside XML file. Right now I am trying to create an extension, which can generate XML string from that hierarchical structure, but first I want to make some sort of research what is the most efficient way to do that? ant what is the easiest way?

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  • Redirect to prevent dup submission...but then you loose existing data

    - by coffeeaddict
    Here's the scenario User is on your checkout.aspx page Somewhere in the process, when clicking the pay button, you redirect the user to an intermediate page (before the confirmation page) to do some other logic. That intermediate page performs whatever logic based on a querystring flag you sent with the redirect from the checkout page This intermediate page also serves as an error page. So if any logic in the intermediatePage.aspx.cs fails I'm setting a message to be displayed on this page to the user If I refresh, that querystring value is still in the url..hence when it hits my Page_Load again, then the server-side logic is called & run again and I don't want this to happen The avoid this behavior/problem, the logical next step is to do a redirect back to the same page if they refresh (not sure how you'd catch that) to get rid of that querystring But when you redirect back to the same page your error message is gone, lost in the redirect therefore you end up showing them the same page but all values for the error message are now gone I do not want to solve this with Javascript either. I am not sure the best way to handle this.

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  • How to design model for multi-tiered data?

    - by Chris
    Say I have three types of object: Area, Subarea and Topic. I want to be able to display an Area, which is just a list of Subareas and the Topics contained in those Subareas. I never want to be able to display Subareas separately - they're just for breaking up the Topics. Topics can, however, appear in multiple Areas (but probably under the same Subarea). How would I design a model for this? I could use ForeignKey from Topic to Subarea and from Subarea to Area, but it seems unnecessarily complex given that I never want to interact with subareas themselves. Also, none of these objects are ever altered or added to by the user. They're just for me to represent information. Maybe there is a better way to represent it all?

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  • Region or ItemsSource for large data set in ListBox

    - by Ryan
    I'm having trouble figuring out what the best solution is given the following situation. I'm using Prism 4.1, MEF, and .Net 4.0. I have an object Project that could have a large number (~1000) of Line objects. I'm deciding whether it is better to expose an ObservableCollection<LineViewModel> from my ProjectViewModel and manually create the Line viewmodels there OR set the ListBox as it's own region and activate views that way. I'd still want my LineViewModel to have Prism's shared services (IEventAggregator, etc.) injected, but I don't know how to do that when I manually create the LineViewModel. Any suggestions or thoughts?

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  • Fastest way for inserting very large number of records into a Table in SQL

    - by Irchi
    The problem is, we have a huge number of records (more than a million) to be inserted into a single table from a Java application. The records are created by the Java code, it's not a move from another table, so INSERT/SELECT won't help. Currently, my bottleneck is the INSERT statements. I'm using PreparedStatement to speed-up the process, but I can't get more than 50 recods per second on a normal server. The table is not complicated at all, and there are no indexes defined on it. The process takes too long, and the time it takes will make problems. What can I do to get the maximum speed (INSERT per second) possible? Database: MS SQL 2008. Application: Java-based, using Microsoft JDBC driver.

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  • viewing data using php and mysql

    - by circle
    hello, i'm circle.very new in php and mysql.i need to develop a website include with database.but i have a problem with this. i'm using php and sql to develop it.my task is: i have two table, investor and commission. investor have three level which is coordinator, consultant and participant.what should i do is, only coordinator can add consultant and participant in their profile.and only coordinator can add participant in their profile. so here, when investor was login, and they go to view commission, they only can see their owned coordinator and participant. but i'm stuck when they want to view the commission.maybe it only a simple thing, but i cannot solved it. help me..:(

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  • Simple C++ container class that is thread-safe for writing

    - by conradlee
    I am writing a multi-threaded program using OpenMP in C++. At one point my program forks into many threads, each of which need to add "jobs" to some container that keeps track of all added jobs. Each job can just be a pointer to some object. Basically, I just need the add pointers to some container from several threads at the same time. Is there a simple solution that performs well? After some googling, I found that STL containers are not thread-safe. Some stackoverflow threads address this question, but none that forms a consensus on a simple solution.

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  • TextBox change is not saved to DataTable

    - by SeaDrive
    I'm having trouble with a simple table edit in a Winform application. I must have missed a step. I have a DataSet containing a DataTable connected to a database with a SqlDataAdapter. There is a SqlCommandBuilder on the SqlDataAdapter. On the form, there are TextBoxes which are bound to the DataTable. The binding was done in the Designer and it machine-produced statements like this: this.tbLast.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.belkData, "belk_mem.last", true)); When I fill the row in the DataTable, the values from the database appear in the textboxes, but when I change contents of the TextBox, the changes are apparently not being going to the DataTable. When I try to save change both of the following return null: DataTable dtChanges = dtMem.GetChanges(); DataSet dsChanges = belkData.GetChanges(); What did I forget? Edit - response to mrlucmorin: The save is under a button. Code is: BindingContext[belkData, "belk_mem"].EndCurrentEdit(); try { DataSet dsChanges = belkData.GetChanges(); if (dsChanges != null) { int nRows = sdaMem.Update(dsChanges); MessageBox.Show("Row(s) Updated: " + nRows.ToString()); belkData.AcceptChanges(); } else { MessageBox.Show("Nothing to save.", "No changes"); } } catch (Exception ex) { MessageBox.Show("Error: " + ex.Message); } I've tried putting in these statements without any change in behavior: dtMem.AcceptChanges(); belkData.AcceptChanges();

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  • Use applescript to write iCal data to file

    - by Guy
    I am trying to get applescript to read todays ical events and write them to a file. The code is as follows: set out to "" tell application "iCal" set todaysDate to current date set time of todaysDate to 0 set tomorrowsDate to todaysDate + (1 * days) repeat with c in (every calendar) set theEvents to (every event of c whose start date = todaysDate and start date < tomorrowsDate) repeat with current_event in theEvents set out to out & summary of current_event & " " end repeat end repeat end tell set the_file to (((path to documents folder) as string) & "DesktopImage:ical.txt") try open for access the_file with write permission set eof of the_file to 0 write out to the_file close access the_file on error try close access the_file end try end try return out The ical items are getting returned correctly and the file ical.txt is created correctly in the folder Documents/DesktopImage, but the file is blank. Even if I substitute write out to the_file with write "Test string" to the_file it still comes up blank any ideas? Ty

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  • How to insert form data into MySQL database table

    - by Richard
    So I have this registration script: The HTML: <form action="register.php" method="POST"> <label>Username:</label> <input type="text" name="username" /><br /> <label>Password:</label> <input type="text" name="password" /><br /> <label>Gender:</label> <select name="gender"> <optgroup label="genderset"> <option value="Male">Male</option> <option value="Female">Female</option> <option value="Hermaphrodite">Hermaphrodite</option> <option value="Not Sure!!!">Not Sure!!!</option> </optgroup> </select><br /> <input type="submit" value="Register" /> </form> The PHP/SQL: <?php $username = $_POST['username']; $password = $_POST['password']; $gender = $_POST['gender']; mysql_query("INSERT INTO registration_info (username, password, gender) VALUES ('$username', '$password', '$gender') ") ?> The problem is, the username and password gets inserted into the "registration_info" table just fine. But the Gender input from the select drop down menu doesn't. Can some one tell me how to fix this, thanks.

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  • Pivot to obtain EAV data

    - by Snowy
    I have an EAV table (simple key/value in every row) and I need to take the 'value' from two of the rows and concat them into a single row with a single column. I can't seem to get through the part where I just have the pivot straight. Can anyone help me figure this out? Declare @eavHelp Table ( [Key] VARCHAR (8) NOT NULL, [Value] VARCHAR (8) NULL ) Insert Into @eavHelp Values ( 'key1' , 'aaa' ) Insert Into @eavHelp Values ( 'key2' , 'bbb' ) Select * From @eavHelp Pivot ( Min( [Value] ) For [Value] in ( hmm1 , hmm2 ) ) as Piv Where [Key] = 'key1' or [Key] = 'key2' That makes: Key hmm1 hmm2 -------- -------- -------- key1 NULL NULL key2 NULL NULL But what I want to make is: hmmmX ----- aaa;bbb

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  • Endless saving of CoreData Context

    - by Robert
    Sometimes I noticed that a 'save:' operation an a ManagedObjectContext never returns and consumes 100% CPU. I'm using an SQL Store in a GarbageCollected environment (Mac OS X 10.6.3). The disk activity shows about 700 KB/s writing. While having a look at the folder that contains the sqlite database file the "-journal" file appears and disappears, appears and disappears, ... This is part of the call graph from the process analysis: 2203 -[NSManagedObjectContext save:] 1899 -[NSPersistentStoreCoordinator(_NSInternalMethods) executeRequest:withContext:] 1836 -[NSSQLCore executeRequest:withContext:] 1836 -[NSSQLCore saveChanges:] 1479 -[NSSQLCore performChanges] ... 335 -[NSSQLCore recordChangesInContext:] ... 20 -[NSSQLCore rollbackChanges] ... 2 -[NSSQLCore prepareForSave:] ... 62 -[NSPersistentStoreCoordinator(_NSInternalMethods) _checkRequestForStore:originalRequest:andOptimisticLocking:] ... 1 -[NSPersistentStore(_NSInternalMethods) _preflightCrossCheck] ... 184 -[NSMergePolicy resolveConflicts:] ... 120 -[NSManagedObjectContext(_NSInternalChangeProcessing) _prepareForPushChanges:] ... Everything a happening in the main GUI thread. Any ideas what I can to do to resolve the problem?

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  • Storing records in a dropdownlist from DB without using LINQ Data source

    - by user1318369
    I have a website for dance academy where Users can register and add/drop dance classes. In the web page to drop a particular dance, for a particular user, the dropdown displays her registered dances. Now I want to delete one of the dances from the list. So i'll remove the row from the table and also from the dropdownlist. The problem is that everytime the item with the lowest ID (index) is getting deleted, no matter which one the user selects. I think I am storing the DataTextField and DataValueField for the dropdown incorrectly. Can someone please help me out? The code is: private void PopulateDanceDropDown() { var registereddanceList = from dd in context.DANCER_AND_DANCE where dd.UserId == dancerId select new { Text = dd.DanceName, Value = dd.DanceId }; dances.DataSource = registereddanceList; dances.DataTextField = "Text"; dances.DataValueField = "Value"; dances.DataBind(); } protected void dropthedance(object o, EventArgs e) { String strDataValueField = dances.SelectedItem.Value; int danceIDFromDropDown = Convert.ToInt32(strDataValueField); var dancer_dance = from dd in context.DANCER_AND_DANCE where dd.DanceId == danceIDFromDropDown select dd; foreach (var dndd in dancer_dance) { context.DANCER_AND_DANCE.DeleteOnSubmit(dndd); } try { context.SubmitChanges(); } catch (Exception ex) { Console.WriteLine(ex); } PopulateDanceDropDown(); }

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  • help with t-sql data aggregation

    - by stackoverflowuser
    Based on the following table Area S1 S2 S3 S4 -------------------- A1 5 10 20 0 A2 11 19 15 20 A3 0 0 0 20 I want to generate an output that will give the number of columns not having "0". So the output would be Area S1 S2 S3 S4 Count ------------------------- A1 5 10 20 0 3 A2 11 19 15 20 4 A3 0 0 0 20 1

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  • Maintaining property lists for xCode projects

    - by William Jockusch
    My project currently contains two largish property lists. One is currently 20KB; another is 8KB. So far, I have been maintaining them with xCode's property list editor. This is manageable but also a bit clunky. I am wondering if other people have better ways of doing this? So far, my lists consist of nested arrays of strings. The depth is not uniform.

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  • How to throw meaningful data in exceptions ?

    - by ZeroCool
    I would like to throw exceptions with meaningful explanation ! I thought of using variable arguments worked fine but lately I figured out it's impossible to extend the class in order to implement other exception types. So I figured out using an std::ostreamstring as a an internal buffer to deal with formatting ... but doesn't compile! I guess it has something to deal with copy constructors. Anyhow here is my piece of code: class Exception: public std::exception { public: Exception(const char *fmt, ...); Exception(const char *fname, const char *funcname, int line, const char *fmt, ...); //std::ostringstream &Get() { return os_ ; } ~Exception() throw(); virtual const char *what() const throw(); protected: char err_msg_[ERRBUFSIZ]; //std::ostringstream os_; }; The variable argumens constructor can't be inherited from! this is why I thought of std::ostringstream! Any advice on how to implement such approach ?

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  • ORM Against a Service-Wrapped Data Source

    - by blaster
    We are tasked with migrating an existing set of entities (currently POCOs persisted with NHibernate against an MSSQL database) to now persist to some kind of web service (yet to be built, either RESTful or SOAP-based, and that we control). I like how NHibernate encapsulates the persistence concerns and lets us maintain a logic-rich, persistence-agnostic domain model. Is there any way to make NHibernate talk to a web service at the back end instead of a SQL database directly? In other words, can "service instead of SQL database" be treated as a persistence implementation detail and allow us to continue to use NHibernate? Am I asking the right question? :)

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  • MySQL: Selecting One Record When Others Have Same Data

    - by LoganFrederick
    I have a table of cities that all share the same area code: 367 01451 Harvard Worcester Massachusetts MA 978 Eastern 368 01452 Hubbardston Worcester Massachusetts MA 978 Eastern 369 01453 Leominster Worcester Massachusetts MA 978 Eastern The table has multiple area codes, all with multiple cities. What I'd like to do is only select one city from each area code and delete any extra cities from duplicate area codes. What would be the best query to accomplish this? I believe: http://stackoverflow.com/questions/596629/mysql4-sql-for-selecting-one-or-zero-record Is coming close to what I need but didn't quite get what/how those answers were working. Note The "978" row is the "area_code" row, table name is "zip_code".

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  • Create a dataset: extract features from text documents (TF-IDF)

    - by BigG
    I've to create a dataset from some text files, writing them as vectors of features. Something like this: doc1: 1,0.45 6,0.001 94,0.1 ... doc2: 3,0.5 98,0.2 ... ... each position of the vector represent a word, and the score is given by something like TF-IDF. Do you know some library/tool/whatever for this? (java is better)

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  • What is the fastest (to access) struct-like object in Python?

    - by DNS
    I'm optimizing some code whose main bottleneck is running through and accessing a very large list of struct-like objects. Currently I'm using namedtuples, for readability. But some quick benchmarking using 'timeit' shows that this is really the wrong way to go where performance is a factor: Named tuple with a, b, c: >>> timeit("z = a.c", "from __main__ import a") 0.38655471766332994 Class using __slots__, with a, b, c: >>> timeit("z = b.c", "from __main__ import b") 0.14527461047146062 Dictionary with keys a, b, c: >>> timeit("z = c['c']", "from __main__ import c") 0.11588272541098377 Tuple with three values, using a constant key: >>> timeit("z = d[2]", "from __main__ import d") 0.11106188992948773 List with three values, using a constant key: >>> timeit("z = e[2]", "from __main__ import e") 0.086038238242508669 Tuple with three values, using a local key: >>> timeit("z = d[key]", "from __main__ import d, key") 0.11187358437882722 List with three values, using a local key: >>> timeit("z = e[key]", "from __main__ import e, key") 0.088604143037173344 First of all, is there anything about these little timeit tests that would render them invalid? I ran each several times, to make sure no random system event had thrown them off, and the results were almost identical. It would appear that dictionaries offer the best balance between performance and readability, with classes coming in second. This is unfortunate, since, for my purposes, I also need the object to be sequence-like; hence my choice of namedtuple. Lists are substantially faster, but constant keys are unmaintainable; I'd have to create a bunch of index-constants, i.e. KEY_1 = 1, KEY_2 = 2, etc. which is also not ideal. Am I stuck with these choices, or is there an alternative that I've missed?

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  • ASP.NET DynamicData: Whats happening during an update?

    - by Jens A.
    I am using ASP.NET DynamicData (based on LINQ to SQL) on my site for basic scaffolding. On one table I have added additional properties, that are not stored in the table, but are retrieved from somewhere else. (Profile information for a user account, in this case). They are displayed just fine, but when editing these values and pressing "Update", they are not changed. Here's what the properties look like, the table is the standard aspnet_Users table: public String Address { get { UserProfile profile = UserProfile.GetUserProfile(UserName); return profile.Address; } set { UserProfile profile = UserProfile.GetUserProfile(UserName); profile.Address = value; profile.Save(); } } When I fired up the debugger, I've noticed that for each update the set accessor is called three times. Once with the new value, but on a newly created instance of user, then once with the old value, again on an new instance, and finally with the old value on the existing instance. Wondering a bit, I checked with the properties created by the designer, and they, too, are called three times in (almost) the same fashion. The only difference is, that the last call contains the new value for the property. I am a bit stumped here. Why three times, and why are my new properties behaving differently? I'd be grateful for any help on that matter! =)

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